1. Field of the Invention
The present invention relates generally to digital camera modules and, more particularly, to a digital camera module which improves image quality.
2. Discussion of the Related Art
Generally, digital cameras are image recording media capable of photographing a plurality of still images without using film. Such a digital camera typically uses an image pickup device, which is a kind of semiconductor device, such as a charge coupled device (CCD) or complementary metal oxide semiconductor (CMOS). In the digital camera, an object image formed on the image pickup device through a lens is converted into an electrical signal by the image pickup device, and the electrical signal is stored as a digital signal in a mobile phone or PDA in which the digital camera is mounted.
A digital camera module, as shown in FIG. 3, a lens barrel 10, a lens holder 12, and an image pick-up module 14. The lens barrel 10 has an external thread 102, and the lens holder 12 has an internal thread 122. The lens barrel 10 is received in the lens holder 12 via the thread engagement between the external thread 102 and the internal thread 122. The image pick-up module 14 includes a base plate 142 and an image pick-up chip 144. The lens holder 12 is fixed on the base plate 142. During auto focusing, a distance between the lens barrel 10 and the image pick-up chip 144 is slightly adjusted to make the digital camera module focus by means of adjusting the thread engagement of the internal thread 122 of the lens holder 12 and the external thread 102 of the lens barrel 10. Lastly, the lens holder 12 is secured on the base plate 142 via adhesive.
However, dust and/or particle pollution/contamination associated with friction between the lens barrel 10 and the lens holder 12 may fall onto the image pick-up chip 144, thus affecting image quality of the digital camera module.
What is needed, therefore, is a digital camera module which overcomes the above-described problem.